An Ultrathin, Fast‐Response, Large‐Scale Liquid‐Crystal‐Facilitated Multi‐Functional Reconfigurable Metasurface for Comprehensive Wavefront Modulation

Abstract

The rapid advancement of prevailing communication and sensing technologies necessitates cost‐effective millimeter‐wave arrays equipped with a massive number of phase‐shifting cells to perform complicated beamforming tasks. Conventional approaches employing semiconductor switch/varactor components or tunable materials encounter obstacles such as quantization loss, high cost, high complexity, and limited adaptability for realizing large‐scale arrays and operating at millimeter‐wave frequencies. Here, we report a low‐cost, ultrathin, fast‐response, and large‐scale solution relying on advanced metasurface (i.e., the 2D version of a bulk 3D metamaterial) concepts combined together with ultrathin liquid crystal (LC) materials requiring a layer thickness of only 5 μm. Rather than immersing resonant structures in LCs, a joint material‐circuit‐based strategy is devised, via integrating deep‐subwavelength‐thick nematic LCs into slow‐wave structures, to achieve constitutive metacells (i.e., artificial atoms or meta‐atoms) with continuous phase shifting and stable reflectivity. A LC‐facilitated reconfigurable metasurface system containing more than 2300 metacells is realized with its unprecedented comprehensive wavefront manipulation capacity validated through three diverse beamforming functions, including beam focusing/steering, reconfigurable OAM‐carrying beams, and tunable holograms, demonstrating a milli‐second‐level function‐switching speed. The proposed methodology offers a paradigm shift for modulating electromagnetic waves in a non‐resonating broadband fashion with fast‐response and low‐cost properties by exploiting functionalized LC‐enabled metasurfaces. Moreover, it is expected that this extremely agile metasurface‐enabled antenna technology will facilitate a transformative impact on communication/sensing systems and empower new possibilities for wavefront engineering and diffractive wave calculation/inference.This article is protected by copyright. All rights reserved